An inflator for inflating a vehicle occupant protection device, such as an air bag, contains a source of inflation fluid for inflating the air bag. In a particular type of inflator, the source of inflation fluid comprises a body of ignitable gas generating material. That type of inflator further includes an ignitor. The ignitor is actuated so as to ignite the body of gas generating material when the vehicle experiences a condition, such as sudden deceleration, which is indicative of a collision and when that condition is above a predetermined level that indicates a collision for which inflation of the air bag is desired. As the gas generating material burns, it generates a volume of inflation gas. The inflation gas is directed into the vehicle air bag to inflate the air bag. When the air bag is inflated, it extends into the vehicle occupant compartment and helps to protect the vehicle occupant.
It is desirable to provide a gas generating material which includes, among other features, stable and relatively inexpensive components, a short ignition period, a burn rate which is rapid but without explosive effects, and a high bulk density so that only a small amount of the gas generating material is required to produce a large amount of nontoxic and non-noxious gases.